Power press tool or the like



Sept. 7, 1937.

H. SINCLAIR ET AL POWER PRESS TOOL OR THE LIKE Filed Dec. 1, 1953 s Sheets-Sheet 1 6 I 5. I J 3 7 f r v if? m e N mm w W v N ar M I 0 wk av HA 7 Sept. 7, 1937. H. SINCLAIR in AL POWER PRESS TOOL OR THE LIKE Filed Dec. 1,. 1933 3 Sheets-$heet 2 IN VEN TOPS 1d Sinclair Arlbu r Fraser M Z; ATTORNEYS Sept. 7, 1937. H. SINCLAIR ET AL 2,092,092

POWER PRESS TOOL OR THE LIKE Filed Dec. 1, 1933 3 Sheets-Sheet 3 8 ml YENTOE'S Hora/d Sinclair Arfhur Fraser the plunger type,

With such an arrangement it has been found that Patented Sept. 7, 1937 UNITED STATES PATENT omen rowan mass TOOL on THE LIKE Harold Sinclair,

Surbiton,

and Andrew Fraser,

Parley, England In Great Britain December 1, 1932 Application December 1,1933, Serial No. 100,400

9 Claims.

plied to effect the forming operation.

In one known arrangement a press is actuated by a hydraulic ram, supplied with working liquid by a positive displacement pump, for example of driven by a suitable motor.

the pump must be driven relatively slowly when the delivery pressure is approaching its maximum in order to reduce the destructive hammering of the pump valves on their seats under high pressure, and in consequence run the high-pressure pump slowly and to provide additional mechanism, such as an auxiliary lower-pressure fluid supply or an auxiliary smallbore ram, if it is desired to secure a relatively rapid initial movement of the tool over the part of its stroke where the driving force is low.

An object of the present invention'is the provision of improved methods and means for operating power press tools or the like, which are relatively simple and nevertheless enable the desired motion of the tool to be satisfactorily performed and easily controlled.

In the method of operating power press tools or the like according to the present invention, power is transmitted from a driving motor to the driving member of the tool through a hydraulic coupling of the kinetic type, the slip in the hydraulic coupling serving automatically to reduce the speed of the tool ofiered to movement of the driving member increases and to stop the tool when the resistance rises to a predetermined value, although the driving motor continues to rotate.

press tool or the like the present invention, means for transmitting power from a driving motor to the tool of the press comprise a hydraulic positive displacement hydraulic positive displacement pump which feeds thehydraulic motor, and a hydraulic coupling of the kinetic type through which the pump is driven and which serves to vary the pump speed automatically and inversely with respect 55 to the resistance offered to movement of the tool.

v10 having a predetermined maximum valuc is ap-- as the resistance I A hydraulic coupling adapted to drive a press or the like by our improved method preferably comprises means for varying the slip characteristic thereof, and it may be provided with a scale so calibrated as to indicate the maximum pres- 5 I the press can generate and an indicator co-operating with the scale and adapted to, give a reading varying in accordance with variation made in the slip characteristic of the coupling.

The invention will be described by way 01 example with reference to the accompanying dia-.

grammatic drawings, in which,

Fig. 1 is a side elevation of a moulding press. Fig. 2 is a sectional side elevation of a part 5 shown in Fig. 1,

Fig. 3 is an end elevation of the part shown in Fig. 2,

Fig. 4 is a diagram of a valve shown in Fig. 1, in an alternative position,

Fig. 5 is a part sectional side elevation of an alternative arrangement, taken on the line in Fig. 6,

Fig. 6 is a part sectional end elevation of the arrangement shown in Fig. 5,

Figs. '1 and 8 are part sectional side elevations of alternative forms of press,

Fig. 9 is a graph of a typical pressure/ slip char acteristic curve of the type of apparatus shown in .Fig. 2.

Rererrin 30 to Figs. 1 m4, a hydraulic press having a movable crosshead l is actuatedby a hydraulic displacement motor in the form of a ram 2 which is supplied with working fluid by a positive displacement radial pump 3 of type, having a driving shait 3' which forms the driving member of the press. The pump driven by anelectric motor 4, which may be of the alternating-current squirrel-cage type, through a hydraulic coupling 5 or the kinetic 40 In the present example this coupling is provided with means which provide a slip characteristic especially suited to the particular operating conditions, as described in patent specification No. coupling 5 (Figs. 2 and 3) is provided with a vaned driving member 6 coupled to the shaft of A filling-plug I2 is screwed into a dished cover known 35 1,963,720 dated June 19, 1934. The 45' a scale I5, which may be marked in tons, on the periphery oi the casing l3.

Working liquid for the press I is contained in' a tank l6 arranged to feed a pump inlet pipe II. A pump delivery pipe I8 is provided with twov branches, one of. which passcontrol valve 20 to the tank l6, and'the other of which leads toa niulti-port valve IS The driving motor 4 runs continuously n and as long as the by-pass valve 20 is open, the pump 3 merely returns liquid to "the tank l6. To raise the valve I9 is set-in the position shown in Fig. 1, and the by-pass valve 20 is coupling is cold, so as pansion of the liquid.

In an alternative arrangement shown in Figs. 5

of which communicates by a passage 30 in the manifold 26 with a port 3|. Th'e port 3| also communicates with the working circuit of the coupling by an inlet passage 32 in the manifold 26 and a passage 33 in the hub of the driven member 1a. The port 3| communicates by a pipe 34 and pump 35 primed. 'A float 31 is connected with a pointer Ma which co-operates-with a fixed scale |5a which may be calibrated in tons.

40 which is somewhat through the passages 32 and 33 into the coupling working circuit.

In Fig. 7 is shown a simple form of mechanical 60 gear driven press. A reversible electric motor 4b having a controller 40 isconnected to a worm 43 through speed-reducing gearing 4t, '42, (the v coupling stalls when a predetermined force is applied by the press. The return stroke is effected by reversing the motor 4b.

In the alternative form of mechanical geared press shown in Fig. 8, the driven member of the hydraulic coupling 5 is connected to a worm-41 meshing with a wheel 48 keyed to a screwed shaft '49 which engages an internally threaded portion 50 of the crosshead lc.

Where a group of hydraulic presses are required to'perform similar operating cycles, a single pressure-generating unit comprising a hydraulic coupling and a high-pressure pump may be employed to serve the several presses in rotation.

We claim:

1. A power press tool comprising a tool member, a motor driven shaft adapted to rotate continuously, a rotatable tool driving member, and a hydraulic coupling having a vaned impeller element drivably connected with said shaft, and a vaned runner element drivably connected with said tool driving member and disposed adjacent to said impeller so as' to form therewith an annular working circuit for coupling liquid, said liquid permitting continuous slipping retardation of said runner element to increasing extents under increasing loads, and said hydraulic coupling being of such a size that, whenthe resistance ofiered to movement of the tool member rises to a. predetermined value, said slip reaches 100%, and movement of said driving member ceases, although said shaft continues to rotate.

' 2. A power press tool comprising a tool member, a driving motor adapted to rotate continuously, a rotatable tool driving member, and a hydraulic coupling having a vaned impeller element drivably connected with said motor and a v vaned runner element drivably connected with said tool driving member and disposed adjacent to said impeller element so as to form therewith an annular working circuit for coupling liquid,

tardation of said runner element to increasing extents under increasing loads, and said hydraulic coupling being of such a size that, when the liquid content of the coupling is substantially at a maximum and while said driving motor continlies to rotate, the slip in'the coupling will rise to 100 per cent upon the resistance ofiered by a work-piece to movement of the tool member rising to the maximum, value that the tool member is adapted to withstand.

3. In a power press tool, a tool member, a hydraulic positive displacement motor for actuating the tool member, a hydraulic positive displacement pump for feeding said motor, and including a pump driving shaft, a driving motor, and a hydraulic coupling having a vanedimpeller element drivably connected to said driving motor and a vaned runner element juxtaposed to said impeller element and fixed to said pump driving.

shaft, said elements together forming an annular working circuit for coupling liquid, said liquid permitting the runner element to continuously slip in respect to the impeller element, the extent of slipping increasing under increasing loads, said hydraulic coupling being of such a size that, when the liquid content of the coupling is substantially at'a maximum, and while said driving motor continues to run, the slip in the coupling will rise to per cent upon the resistance offered by a workpiece to movement of the tool member rising to the maximum value that the tool member is adapted to withstand.

4. In a power press tool, a tool member, a hydraulic positive displacement. motor which means for varying the liquid content of said coupling circuit to vary the maximum load which will cause 100% slipping, and a by-pass valve disposed on the delivery side of said pump and operable to release the pressure acting on said hydraulic motor. i

5. A power press tool comprising a tool member, a driving motor adapted to run continuously, a rotatable driving member which serves to actuate the tool member, a hydraulic slippable coupling having a vaned impeller element drivably connected with said motor and a vaned runner element drivably connected with said tool driving member, said coupling elements being juxtaposed to form an annular working circuit for coupling liquid, said liquid permitting the runner element to continuously slip in respect to the impeller element, the extent of slipping increasing under increasing loads, means for varying the slip characteristic of said coupling to vary the maximum load which will cause 100% slipping, an indicator responsive to operation of said slip-varying means, and a scale with which said indicator cooperates, said scale being so calibrated as to register the force exerted by the tool member when said driving member stalls at the end of a press stroke.

6. A power press tool comprising a tool member, a reversible driving motor, a rotatable driving member which serves to actuate the tool member, and a hydraulic slippable coupling having a vaned impeller element drivably connected with said motor and a vaned runner element drivably connected with said tool driving memher, said elements being juxtaposed to form an annular working circuit for coupling liquid, said liquid permitting continuous slipping retardation of said runner element to increasing, extents under increasing loads, and said hydraulic coupling being of such a size as to permit said driving member to stall upon the resistance offered to movement of the tool member rising to a predetermined value, although said motor continues to rotate, and the return stroke of the press being effected by reversing said motor.

7. A power press tool comprising a tool member, a rotatable driving member which serves to actuate the tool member, a reversible electric motor and a hydraulic slippable coupling of the kinetic type connected between said driving member and said motor, said coupling being of such a size as to permit said driving member to stall although the driving motor continues to rotate and permitting said motor to start up in the reverse direction under a light load at the beginning of an opening movement of the press.

8. A power press tool comprising a tool member, a motor driven shaft adapted to rotate continuously, a rotatable tool driving member, and a hydraulic slippable coupling having a vaned impeller drivably connected with said shaft and a vaned runner drivably connected with said tool driving member and forming with said impeller an annular working circuit for coupling liquid, said coupling being of such a size that, when said motor driven shaft is rotating and the liquid content of said coupling is at its maximum, while the resistance to motion of said tool member rises 'from not less than 70% of its maximum value to its maximum value, the slip in said coupling increases, in substantially linear relationship with said resistance, from not more than 50% to 100%.

9. The method of controlling the maximum pressure applied to a work piece in a power press,

which includes driving the tool member by a hy-- draulic coupling of the kinetic type. which HAROLD smcmm'; 

